Methods of producing a methacrylic polymer by bulk polymerization have a merit of excellent productivity as compared with batch mode suspension polymerization, a merit of very excellent transparency of the resulting polymer since auxiliary agents such as a dispersing agent and the like are not required, a merit of no necessity of separation of a reaction solvent in comparison to solution polymerization, a merit of very excellent transparency of the resulting polymer since a residual solvent is not present in the polymer after removal of volatiles, and further a merit of obtaining a polymer excellent in thermal degradation resistance since the amount of a polymerization initiator to be fed to a reaction region is permitted to be very small.
As a method of continuously performing such bulk polymerization of a methacrylic polymer, production methods excellent in productivity using a complete mixing type reactor, a tubular reactor and a volatile removing instrument are investigated.
For example, patent document 1 describes a method wherein in polymerizing using a complete mixing type reactor and a successively placed tubular reactor, a polymerization initiator is further added to a reaction solution extracted from the complete mixing type reactor and the polymerization reaction is carried out in the tubular reactor, to improve polymerization ratio.